Electroplate honing method

ABSTRACT

An electroplate honing technique that utilizes mechanical abrading or honing to clean the metallic surface of a workpiece, then with the tool acting as an electrode, utilizes an electroplate honing cycle to plate or deposit metal on the surface of the workpiece, then terminating the flow of current and utilizing a honing cycle to generate the surface finish desired by mechanical abrasion.

[451 Jan. 25, 1972 United States Patent Elliset al.

3,3l3,7l5 4/l967 Schwartz,.lr..........................,.204/26 [54] ELECTROPLATE HONING METHOD [72] Inventors: Myron P. Ellis, Royal Oak; Richard J. FOREIGN PATENTS OR APPLICATIONS Gavasso, Detroit, both of Mich. 5 83 872 Great Britain Assignee:

Micromatic Hone Corporation, Detroit, Mich.

Primary Examiner-John H. Mack .m m r r U8 w m 5 mm my o n m an AA 0 6 9 1 6 L c 0 d .w H ,d 2

[57] ABSTRACT An electroplate honing technique that utilizes mechanical [2]] Appl. No.:

....204/26, 204/217, 204/224 C23b 5/56,B23p 1/00, B23n 1/02 abrading or honing to clean the metallic surface of a work- .204/26, 217, 224, 143 M piece, then with the tool acting as an electrode, utilizes an [52] US. [51] Int. [58] Field ofSearch.......................

electroplate honing cycle to plate or deposit metal on the sur- Ref ren e Ci d face of the workpiece, then terminating the flow of current and utilizing a honing cycle to generate the surface finish desired by mechanical abrasion.

UNITED STATES PATENTS 2 Claims, 5 Drawing Figures 3,022,232 Bailey et al. 3,267,018 Greening..............................

PATENTED JANZS I972 SHEET 2 BF 3 TOOL ANODE FOR PLATIN G \/CATHODE FOR PLATING D.C.POWER SOUFKZE INVENTORJ PLATING SOLUTION mywo/v R [14/5 g/a/Aeo JTGAVAJUO ATTORNEY PATENTEB JANZS I972 SHEET 3 OF 3 HIGH STONE PRESSURE E R wm O05 P e W L N A E T: c

T N E R R U C PART SOURCE OF D.C. POWER PLATING.

GENERATION OF' SURFACE FINISH 19 ave /v A T TORNEV ELECTROPLATE HONING METHOD BACKGROUND OF THE IN YENTION 1. Field of the Invention This invention relates tothe honing art and more particularly to an electroplate honing method whereby the surface of themetal is first cleaned by a honing process, then plated, so that the plated surface is mechanically honed to the desired surface characteristics.

2. Description of the Prior Art It is known and recognized to utilize plating and burnishing or polishing at the same time. That is, the surface of the material is polished or burnished at thesame time that the plating solution is pumped into the environmental area. Other processes involve a simultaneous bumishing and plating operation while the workpiece is immersed in a plating solution. Another. method is to utilize an electromechanical honing cycle to clean the metallic surface, then electroplating the metallic surface, and finally mechanically abrading the surface, as further described in applicants copending application Ser.No.838,113,filed.luly 1,1969.

SUMMARY OF THE INVENTION According to the present invention, the electroplate honing method combines the surface cleaning characteristics of honing, the high metal deposition rate of high-current density electroplating and the accurate abrading of honing. It eliminates the need for acid etching of the surface to be plated and/or the masking of adjacent surfaces. The metal is deposited only on surfaces in close proximity to the electrode. The electrode in this instance is also the honing tool.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front perspective view of an electroplate honing apparatus made in accordance with the principles of the present invention;

FIG. 2 is a fragmentary perspective view of a workpiece being operated by the electroplate honing tool to illustrate the principles of the present invention;

FIG. 3 is a schematic representation in which the surface of the workpiece is being cleaned;

FIG. 4 is a schematic representation in which the surface of the workpiece is being plated;

FIG. 5 is a schematic representation showing the surface of the workpiece being abraded.

GENERAL DESCRIPTION FIG. 1 shows a perspective view of an illustrative embodiment which comprises a hollow base generally indicated by the numeral on which is mounted a column generally indicated by the numeral 11. As shown. the numeral 12 generally indicates a spindle and/or ram assembly on which is operatively mounted a tool spindle generally indicated by the numeral 13. A tool member generally indicated by the numeral 14 is connected to the spindle 13. The tool member 14 extends downwardly into operative engagement with the workpiece 16 held in a workpiece fixture 17 that is disposed in a transparent fixture enclosure 15. The workpiece 16 is illustrated as comprising a gear. The honing apparatus includes means for reciprocating and rotating the tool member 14 relative to the workpiece 16 as described in detail hereinafter. The tool member 14 carries means for maintaining it in a spaced apart position relative to the surface of the workpiece 16 which is being machined in a manner described in U.S. Pat. No. 3,390,068, issued to M. P. Ellis et al. on June 25, 1968, and application Ser. No. 838,113, filed July 1, 1969, and assigned to the present assignee of the application. The plating solution is supplied to the gap or space between the tool 14 and the workpiece surface during the machining operation and direct current is simultaneously passed between the workpiece 16 and the tool member 14 in a manner described hereinafter.

As shown in FIG. 1. the spindle head assembly 12 is slidably mounted for vertical reciprocating movement on a pair of vertical, spaced apart guide members 17 and 18. The spindle head assembly 12 includes the central housing 19 on each side of which is integrally formed the vertically disposed guide sleeves 20 and 21.

The spindle head assembly 12 is adapted to be reciprocated upwardly and downwardly by a pair of hydraulic cylinders not shown but described in the hereinabove mentioned Pat. to Ellis et al. U.S. Pat. No. 3,390,068. It will be understood that the hydraulic cylinders may be operated and controlled by any suitable hydraulic controlled circuit means. An illustrative control circuit which may be employed to operate the hydraulic cylinders is shown in FIG. 51 of the hereinabove mentioned patent to Ellis et al.

The machine used is basically a honing machine such as described in the above mentioned patent. A rectifier supplies the direct current to the operation. During the plating the honing tool acts as the anode, having a positive potential, and the workpiece is the cathode. The plating solution is pumped into the gap between the tool and the surface being plated.

A typical plating cycle is as follows:

I. A short period, approximately 10 seconds, is used to clean the surface by a honing or mechanical abrading process. The tool is expanded so that the stones 22 are abrading the surface 23 of the workpiece 16. The plating solution is flooding the tool and the workpiece at the gap between the surface 23 of the workpiece and the tool 14.

2. At the end of this time period current flow is initiated so that the workpiece has a negative potential as shown in FIG. 4. The pressure of the honing stones 22 is reduced. Consequently, metal is plated onto the surface uniformly at a rate depending on the solution being used, the current density, and in some cases the temperature of the solution. The stones are in a low stone pressure state thereby abrading the surface throughout the plating cycle to eliminate treeing, refine the grain structure of the plated metal and generate accurate geometry.

3. When the bore is-plated to the desired size, the flow of current is terminated and the pressure on the stones 22 is increased, as shown in FIG. 5, to generate the surface finish desired. That is, during the first and last stages there is no cur rent flow between the tool and the workpiece.

Any amount of metal may be plated onto the surface that is kept clean by the honing stones. Termination of the plating may be achieved by a predetermined timing cycle or an automatic in-process gaging.

Plating rate Time to deposit As shown in FIG. 2, the pressure of the honing stones may be accomplished by movement of a cone means 30 connected to a rod 31 slidable in tool 14. The rod 31 is connected to a piston 33 slidable in chamber 35. Movement of piston 33 in upward or downward directions is caused by providing fluid pressure through lines 37 and 39, depending on the direction of movement. The tool 14 is itself totally reciprocated and rotated in a manner well known in the art and in the above mentioned patent to Ellis et al.

For purposes intended, the description and drawings hereinabove is related to finishing the interior bore surfaces of a workpiece, however, the method described herein can be applied to other structures, such as exterior surfaces of a cylindrical or spherical object, and flat plane surfaces.

We claim:

1. A method for finishing the surface of a workpiece with a tool having an electrically conductive tool body portion and at least one abrasive member supported by and adjustable outwardly from said tool body portion comprising the steps of:

with a honing tool having an electrically conductive tool body and at least one abrasive member supported by and adjustable outwardly from said tool body, comprising the steps of:

1. providing relative movement between the honing tool 1. providing relative movement between the honing tool 5 and the work surface;

and the work surface; 2. maintaining said electrically conductive tool body in a 2. maintaining said electrically conductive tool body porspaced rel i n hip I0 Ih6 Work f tion in aspaced relationship to the o k f 3. advanc ng the abrasive member into abrasive engage- 3. flowing a plating solution between the work surface and men! with the W fa I m v m al me hanithe electrically conductive tool body portion; from the Work Surface;

4, honing the work surface t clean id f 4. flowing a plating electrolyte between the work surface 5. initiating current flow with the workpiece negative potenand f elecmcally conductive l yi tial, so that metal is plated onto the surface of the work- 5 homng the Work surface to Clean 531d Suffflcfi; piece; 6. initiating the flow of direct electric current from said work 6. keeping the abrasive member rubbing on the work sursufface 581d elecmca! condlfcnve tool body through face during plating to keep the surface clean, refine the 581d PF electrolyte Plate said Y 5911899; grain structure of the plated material, and correct errors PP y low'abl'aslYe Pf against 531d Work Surface i geometric h as said work surface 18 being plated;

7. terminating the supply of direct current; and, termillating h pp y dll'ect CulTePt;

8. advancing the abrasive member into increasing pressure 20 PP a abraswe P 3 said work with the work surface to remove the metal mechanically face; form said work surface and generate a controlled cut surretfactmg the abraslve member after a Predetermmed f fi i h time interval.

2. A method of plating and honing a metallic work surface 

2. A method of plating and honing a metallic work surface with a honing tool having an electrically conductive tool body and at least one abrasive member supported by and adjustable outwardly from said tool body, comprising the steps of:
 2. maintaining said electrically conductive tool body in a spaced relationship to the work surface;
 2. maintaining said electrically conductive tool body portion in a spaced relationship to the work surface;
 3. flowing a plating solution between the work surface and the electrically conductive tool body portion;
 3. advancing the abrasive member into abrasive engagement with the work surface to remove metal mechanically from the work surface;
 4. flowing a plating electrolyte between the work surface and the electrically conductive tool body;
 4. honing the work surface to clean said surface;
 5. initiating current flow with the workpiece negative potential and the tool positive potential, so that metal is plated onto the surface of the workpiece;
 5. honing the work surface to clean said surface;
 6. initiating the flow of direct electric current from said work surface to said electrically conductive tool body through said plating electrolyte to plate said work surface;
 6. keeping the abrasive member rubbing on the work surface during plating to keep the surface clean, refine the grain structure of the plated material, and correct errors in geometric shape;
 7. terminating the supply of direct current; and,
 7. applying low-abrasive pressure against said work surface as said work surface is being plated;
 8. terminating the supply of direct electric current;
 8. advancing the abrasive member into increasing pressure with the work surface to remove the metal mechanically form said work surface and generate a controlled cut surface finish.
 9. applying a high-abrasive pressure against said work surface; and
 10. retracting the abrasive member after a predetermined time interval. 